Hydraulic servomotor for train controllers and the like



April 28, 1936. I PIEPER H 2,039,186

HYDRAULIC SERVOMOTOR FOR TRAIN CONTROLLERS ANO .THE LIKE Filed 001-. 21,1953 Patented Apr. 28, 1936 PATENT OFFICE HYDRAULIC SERVOMOTOR FOR TRAINCONTROLLERS AND THE LIKE :Henri Pieper, Brussels, Belgium ApplicationOctober 21, 1933, Serial No. 694,676

In Germany October 22, 1932 6 Claims.

My invention relates to a motor driving device for controllers 'ofelectric power vehicles in multiple unit trains, for vehicle doors orsimilar apparatus to be adjusted at difierent points of a circular,rectilinear or other path of motion, in which apparatus a piston servingto drive this apparatus is moved by a pressure liquid and can beconnected, by means of distributing members, at both sides to acharge-reservoir or a discharge reservoir respectively.

According to my invention this driving and controlling device issimplified in its construction and improved'in its mode of operation bythat an electromagnet effects the stopping of the driving piston and ofthe apparatus to be adjusted in the desired position without the aid ofa special valve inserted otherwise in the circuit of the liquid. Forthis purpose, according to my invention, this electromagnet which isexcited after the starting of the apparatus to .be adjusted, effects atthe desired instant through the instrumentality of the engagement of adetent in a grooved disc the stopping of the driving piston and therebyalso the arresting of the pressure liquid. There is thus efiected withsimple means a sudden shifting of the apparatus to be adjusted from oneposition to another and an accurate arrest of the driving piston at thedesired point of the path of motion. The excitation of thiselectromagnet takes place after the starting of the apparatus to beadjusted preferably at the instant at which the detent resting on theperiphery of the grooved disc sets about to enter into the groove whichcorresponds with the desired position and the electromagnet remainsexcited until the driving piston is started again, before which start itis switched ofi for an instant.

The drawing shows in Fig. 1 by way of example one embodiment of myinvention as applied to a driving device to adjust a controller for anelectric power car. Figs. 2 and 3 show the rotating contact drum of thearrangement of Fig. 1 in two positions-differing from the position shownin Fig. 1.

The driving device comprises a driving liquid, for example, oil and acharge reservoir 2 containing compressed gas,-for example, compressedair, a discharge reservoir 4 which is open to the atmosphere and ahydraulic rotary piston motor, which consists of an annular cylinder 3a.and an oscillating blade-like piston 3. The two spatially variablecompartments 3a and 3a", which are formed in the cylinder 3a by means ofthe bladepiston 3, can be placed in communication alternately with thecharge reservoir 2 or the dis charge reservoir 4 by means of adistributing cock 5, which is adjusted by means of an electromagnet 5kin opposition to the action of a spring 51'. When the electromagnet 5kis not excited, the spring 51' holds the cock 5 in the position repre- 5sented in full lines in the drawing, in which the cylinder compartment3a is connected with the pressure reservoir 2 through the ducts 6, I andthe port 5' in the cock, while the cylinder compartment 3a" is connectedto the discharge reservoir 4 by way of the ducts 8, 9 and the ort 5" inthe cock. When the electromagnet 5k is excited, it rotates the cock 5into the position indicated in dotted lines in the drawing, in which thecylinder compartment 3a is connected withthe discharge reservoir 4 andthe cylinder compartment 3a" with the charge reservoir 2. By turning thecock 5 into the one or the other of these two positions the rotation ofthe bladepiston 3 in the clockwise direction or in the oppositedirection of rotation is in this manner effected by the driving liquid.

The shaft ll of the rotary piston 3 carries a disc l3 provided withgrooves l3a and a latchshaped detent l3b is drawn against the peripheryof the disc B by means of a spring I31 and also by means of anelectromagnet l2k when the latter is excited. The electromagnet HR: isdesigned to be powerful enough to arrest the motion of the rotary piston3 and so to stop said piston and the apparatus which is to be adjusted,when the electromagnet coil [2k is switched in and holds the detent I3bin firm engagement with a groove l3a of the disc l3. The spring I31alone is unable to stop the piston 3. The duct I contains a valve Iawhich opens according to the cock 5 and is held closed by means of anelectromagnet 1k, when the latter is excited. A damper Id, the piston ofwhich moves in a liquid and is provided with small openings, permits thevalve la to be opened quickly by switching off the electromagnet ilc butretards the closing movement of this valve when the electromagnet 1k isexcited. The duct 8 possesses a valve 8a which rests on a set-screw 8dunder the action of its weight or of a spring, which set-screw is so setthat the valve 8a ofiers a small opening for the liquid in the directionof flow towards the cylinder 3a and a large opening in the oppositedirection of flow.

The electromagnets 1k and I210 are controlled by means of a drum H),which is coupled with the piston shaft I4 and is provided withcontactpieces Ilia, lflb', llic', Hid, and Hie. The drum Hi can be setin different positions, for example, in four different positionsrelatively to the fixed contacts lOa, lOb. I00, Id and Hie. The circuitsof the electromagnets 1k and HR: also pass through the segments of ahand change-over switch. H, which is connected with the battery l8 oranother source of electric energy. The electromagnet 5k, which controlsthe cock 5, is connected directly to one oi! the segments of thechange-over switch H. The hand-lever oi the change-over switch I! canoccupy four positions corresponding to the four positions of the druml0. When it is a matter of driving a controller 20 for electric motors,the position 0 of the change-over switch I! corresponds to the zeroposition of the controller, the position P. S to the connection of theelectric motors in series with resistances switched in, the position Sto the connection in series without resistances and the position P tothe connection of the electric motors in parallel, while the return ofthe controller into the zero position can take place in one movementwithout intermediate positions. In

order to block the driving device if the current of the electric motorsexceeds a definite amount, a relay which is traversed by said current isprovided, which closes a keeper Ila when the current strength reachesthe determined amount. The switch Ha of the relay ll then connects theelectromagnet l2]: directly with the battery l8 and this electromagneteffects the stopping of the motor 3 and consequently also that of thecontroller of the electric motors, until the motor current resumes itsordinary value.

The driving device works as followsz-When the hand-switch l1 occupiesthe position 0 the drum I0 is also in the position 0 shown in Fig. l andthe electromagnet 1k is excited by way oi! the contact-piece Illa in thedrum in and keeps the valve la closed, while the electromagnets 5k and I2k are switched off. The closedvalve 1a prevents the pressure in thereservoir 2 from acting on the liquid in the cylinder 3a, so that in thelatter no losses of liquid can occur through liquid passing over fromone side of the blade-piston 2 to the other. It the hand switch I! ismoved into the position P. S the electromagnet 1k is switched off sothat the valve 1a can open and at the same time the electromagnet 5k isswitched in, which electromagnet then moves over the cock 5 into theposition drawn in dotted lines, in which position the cylindercompartment 3a is connected to the discharge reservoir 4 and thecylinder compartment 3a" to the charge reservoir 2. The piston 3 and thedrum I0 are consequently set in rotation in the direction of the arrowl5 by means of the driving liquid. As soon as the drum III has reachedthe position P. S shown in Fig. 2 it closes the circuit of theelectromagnet [2k at the contact-piece Hlb', which at this instantbridges over the fixed contacts lfla and I 0b. The excited electromagnetI27: presses the detent l3b into the groove l3a of the disc l3 whichcorresponds to the position P. S. and so arrests instantaneously the'piston 3 and the driving liquid in this position. The excitation of theelectromagnet l2k commences at the instant at which the detent [322 setsabout to fall into the groove l3a corresponding to the position P. S.

When the hand-switch I1 is brought from the position P. S into theposition S, there takes place another switching ofi of the electromagnetl2k, so that the driving liquid can again set in rotation the rotarypiston 3 and the drum l0 and also the apparatus to be adjusted. As soonas the drum l0 reaches the position S shown in Figure 3, itscontact-pieces I00 and we close the circuits of the electromagnets l2kand Us. The electromagnet I 2k again stops the piston 3 and the drumIII, while the closure of the valve Ia produced by means of the excitedelectromagnet 1k is accomplished slowly owing to the retarding action ofthe damper Id. It the hand-switch I7 is brought from the position 8 intothe position P the circuits of the electromagnets 1k and 12k are againbroken by the hand switch I! before it reaches the position P, whichpermits the restarting of the piston 8 and or the drum ID by means ofthe driving liquid because the deenergized electromagnet 1k allows thevalve la to be opened by the pressure oi. the reservoir 2, whilst thedeenergized electromagnet I2k allows the piston I to be driven by thepressure liquid coming from the reservoir 2 through the valve 1a and thepipes I and 8. The drum l0 maintains the break in the circuit of theelectromagnet 1k during its passage from the position S to the positionP whilst it on its; arrival in the position P closes by means of itscontact piece we again the circuit of the electromagnet lk, which on theother hand is completed by the hand switch l1 occupying at this instantthe position P. The excited electromagnet 1k arrests the motion of thedriving liquid by closing the valve la, while the piston 3, which hasnow reached the end of its stroke can be stopped in the position Psimply by means of a stop on the cylinder 30. so that a furtherexcitation of the electromagnet l2k is not necessary.

The electromagnet 51: remains excited in the three positions P. S, S andP of the hand-switch H and during the whole of this time holds the cock5 in the position indicated by dotted lines, in which it connects thecylinder compartment 30:" with the pressure reservoir 2. Since the valve8a has a passage of small cross-section for the driving liquid in thedirection of flow towards the cylinder compartment Be, the movement ofthe piston 3 and consequently of the apparatus to be adjusted can takeplace in the direction of the arrow l5 at only a moderate velocity. Inorder to. return the apparatus to be adjusted into the zero position,the hand-lever I1 is brought back into the position 0 in one movementwithout intermediate positions. On the arrival of the hand-lever H inthe position I] the circuit of the electro-magnet 5k is interrupted, sothat the spring 51' can shift the cock into the position indicated infull lines, in which the pressure-reservoir 2 is connected with thecylinder-compartment 3a and the discharge reservoir 4 with thecylinder-compartment 3a On the other hand during the return of thehand-switch I! from the position P into the position ll theelectromagnet 1k is switched oif for a definite time which is sufficientto allow the valve la to open in consequence of the non-excitation ofthe electromagnet 1k. Since the closure of the valve la on theelectromagnet 1k being switched in again in the position 0 of thehandswitch I? can be accomplished only slowly in consequence of theretarding action of the damper 1d the driving liquid has sufiicient timeto return in the direction of the arrow 19 into the zero position thepiston 3 and the drum l0 and also the apparatus to be adjusted beforethe valve la is completely closed again. The quick return into the zeroposition is facilitated by the valve 8a, which presents a passage with alarge cross-section to the liquid flowing away from the cylindercompartment 3a" towards the discharge reservoir 4.

The arrest of the piston 3 in the zero position, in which theelectromagnet We is not excited, can be eii'ected by means of a stop onthe cylinder in, since the piston in this position is at the other endof its stroke.

My invention may also of course be carried out in details in a mannerdeviating from the example illustrated, a motor with areciprocating'piston being for example employed instead of the rotarypiston motor shown in the drawing.

Having now described the nature of my invention I declare what I claimis:--

1. A hydraulic servo-motor for driving an element step by step andlooking it in any desired step, comprising in combination a chargingreservoir containing liquid under pressure, a cylinder, 9. piston inthis cylinder for driving the apparatus to be adjusted, a dischargingreservoir, distributing means for connecting said cylinder on both itsends alternately to said charging reservoir and to said dischargingreservoir, means for controlling electrically said distributing means, adisc driven by said piston and having grooves corresponding in numberand position to the individual positions of arrest of the apparatus tobe adjusted, a pawl-like organ resting on said grooved disc and capableof engaging in the grooves of said disc, an electromagnet capable ofacting when excited upon said pawl-like organ so as to bring it intoengagement with one of the grooves of said grooved disc and thereby toarrest the driving piston and the pressure liquid, and means forexciting said electromagnet after the starting of the apparatus to beadjusted.

2. A hydraulic servo-motor for driving an element step by step andlooking it in any desired step, comprising in combination a chargingreservoir containing liquid under pressure, a cylinder, a piston in thiscylinder for driving the apparatus to be adjusted, a dischargingreservoir, distributing means for connecting said cylinder on both itsends alternately to said charging reservoir and to said dischargingreservoir, means for controlling electrically said distributing means, adisc driven'by said piston and having grooves corresponding in numberand position to the individual positions of arrest of the apparatus tobe adjusted, a pawl-like organ resting on said grooved disc and capableof engaging in the grooves of said disc, an electromagnet capable ofacting when excited upon said pawl-like organ so as to bring it intoengagement with one of the grooves of said grooved disc and thereby toarrest the driving piston and the pressure liquid, and controlling meansdriven by said piston for exciting said electromagnet at the instant atwhich the pawl-like organ moves to enter into the groove of said disccorresponding to the desired position and for maintaining thisexcitation until said driving piston is started again and manual meansfor switching of! this excitation for a certain time when said piston isto be started again.

3. A hydraulic servo-motor for driving an element step by step andlooking it in any desired step, comprising in combination a chargingreservoir containing liquid under pressure, a cylinder, a piston in thiscylinder for driving the apparatus to be adjusted, a dischargingreservoir, distributing means for connecting said cylinder on both itsends alternately to said charging reservoir and to said dischargingreservoir, means for controlling electrically said distributing means, adisc driven by said piston and having grooves corresponding in numberand position to the individual positions of arrest or the apparatus tobe adjusted, a pawllike organ resting on said grooved disc and capableor engaging in the grooves of said disc, an electromagnet capable ofacting when excited upon said pawl-like organ so as to bring it intoengagement with one of the grooves of said grooved disc and thereby toarrest the driving piston and the pressure liquid, and controlling meansdriven by said piston for exciting said electromagnet at the instant atwhich the pawl-like organ moves to enter intothe groove of said disccorresponding to the desired position and for maintaining thisexcitation until said driving piston is started again and manual meansfor switching off this excitation for a certain time when said piston isto be started again, a valve inserted between the cylinder of saiddriving piston and said charging reservoir and means for electricallycontrolling said valve so as to shut off the supply of liquid to saidcylinder in all positions in which the apparatus to be adjusted remainsstopped during a certain time. i

4. A hydraulic servo-motor for driving an element step by step andlooking it in any desired step, comprising in combination a chargingreservoir containing liquid under pressure, a cylinder, a piston in thiscylinder for driving the apparatus to be adjusted, a dischargingreservoir, distributing means for connecting said cylinder on both itsends alternately'to said charging reservoir and to said dischargingreservoir, means for controlling electrically said distributing means,adisc driven by said piston and having grooves corresponding in numberand position to the individual positions of arrest of the apparatus tobe adjusted, a pawl-like organ resting on said grooved disc and capableof engaging in the grooves of said disc, an electromagnet capable ofacting when excited upon said pawl-like organ so as to bring it intoengagement with one of the grooves of said grooved disc and thereby toarrest the driving piston and the pressure liquid, and controlling meansdriven by said piston for exciting said electromagnet at the instant atwhich the pawl-like organ moves to enter into the groove of said disccorresponding to the desired position and for maintaining thisexcitation until said driving piston is started again and manual meansfor switching off this excitation for a certain time when said piston isto be started again, a valve inserted between said cylinder of saiddriving piston and said charging reservoir, an electromagnet capable ofacting when excited upon said valve so as to close it, a damperconnected to the armature of said electromagnet so as to retard itsclosing action and means for electrically controlling saidelectromagnet.

5. A hydraulic servo-motor for driving an element step by step andlooking it in any desired step, comprising in combination a chargingreservoir containing liquid under pressure, a cylinder, a piston in thiscylinder for driving the apparatus to be adjusted, a dischargingreservoir, distributing means for connecting said cylinder on both itsends alternately to said charging reservoir and to said dischargingreservoir, means for controlling electrically said distributing means, adisc driven by said piston and having grooves corresponding in numberand position to the individual positions of arrest of the apparatus tobe adjusted, a pawl-like organ resting on said grooved disc and capableof engaging in the grooves of said disc, an electromagnet capable ofacting when excited upon said pawl-like organ so as to bring it intoengagement with one of the grooves of said grooved disc and thereby v toarrest the driving piston and the pressure liquid, and controlling meansdriven by said piston for exciting said electromagnet at the instant atwhich the pawl-like organ moves to enter into the groove 01' said disccorresponding to the desired position and for maintaining thisexcitation until said driving piston is started again and manual meansfor switching of! this excitation for a certain. time when said pistonis to be started again, a valve arranged between said cylinder of saiddriving piston and said distributing means and presenting a passage ofcontracted crosssection to the liquid flowing towards said drivingpiston and a passage of large cross-section to the liquid flowing in theopposite direction.

6. A hydraulic servo-motor for driving an element step by step andlooking it in any desired step, comprising in combination a chargingreservoir containing liquid under pressure, a cylinder, a piston in thiscylinder for driving the apparatus to be adjusted, a dischargingreservoir, distributing means for connecting said cylinder on. both itsends alternately to said charging reservoir and to said dischargingreservoir. means for controlling electrically said distributing means, adisc driven by said piston and having grooves corresponding in numberand position to the individual pomtions of arrest of the apparatus to beadjusted, a pawl-like or an resting on said grooved disc and capable ofe aging in the grooves of .said disc, an electromagnet capable' ofacting when excited upon said pawl-like organ so as to bring it intoengagement with one of the grooves of said grooved disc and thereby toarrest the driving piston and the pressure liquid, and controlling meansdriven by said piston for exciting said electromagnet at the instant atwhich the pawl-like organ' moves to enter into the groove of said disccorresponding to the desired position and for maintaining thisexcitation until said driving piston is started again and manual meansfor switching 01! this excitation for a certain time when said piston isto be started again, said driving piston and its cylinder being formedas a rotary piston motor.

- HENRI PIEPER.

